If you are suffering from Asthma or COPD during the day and at night? The propeller is a sensor + software system that uses FDA-cleared technology to make living with Asthma and COPD a little easier. Get a free sensor for your inhaler! They will send you a sensor to attach to your inhaler as soon as you download and sign in to the smartphone app. We're excited to help you have more symptom-free days.